Elsevier

Fluid Phase Equilibria

Volume 299, Issue 1, 15 December 2010, Pages 60-64
Fluid Phase Equilibria

Experimental and predicted excess molar enthalpies of binary mixtures containing 2,2′-oxybis[propane], benzene, butan-1-ol, 2-methylpropan-1-ol, 2-methyl-2-ene-1-propanol at 303.15 K

https://doi.org/10.1016/j.fluid.2010.08.024Get rights and content

Abstract

Excess molar enthalpies HE have been measured for liquid binary mixtures of 2,2′-oxybis[propane] (diisopropylether ‘DIPE’), or, benzene + butan-1-ol, +2-methylpropan-1-ol (isobutanol), +2-methyl-2-ene-1-propanol (isobutenol), +n-heptane at 303.15 K and constant pressure using a C80, Setaram calorimeter. A Redlich–Kister type equation was used to correlate experimental results.

These experimental results, along with our previous data on HE of DIPE + benzene, +cyclohexane [1] are used for estimating interaction parameters in DISQUAC, an extended quasi-chemical group contribution model [2], [3].

Introduction

From a practical point of view, oxygenated compounds, such as ethers and alkanols, are increasingly being used as additives to gasolines owing to their octane-enhancing and pollution-reducing properties [4]. From a theoretical point of view, the study of the thermodynamic behavior of binary mixtures involving branched monoethers, such as diisopropylether with different nature of alcohols, are, of high interest because they make possible to study a number of effects (e.g. steric, proximity or orientational effects…) on the interactions present in the mixtures considered and to test group contribution models for estimating the thermodynamic excess functions of mixtures.

The present work forms a part of our investigation on binary and ternary mixtures containing oxygenate additives (ethers, alcohols) with hydrocarbons (cycloparaffins, aromatics) [1], [5]. Previously, we have reported excess enthalpies of DIPE + benzene, +toluene, +m-xylene, +cyclohexane at 303.15 K [1], [5]. As a continuation of that work, similar measurements have been made for six further binary mixtures: diisopropylether + butan-1-ol, +2-methylpropan-1-ol (isobutanol), +2-methyl-2-ene-1-propanol (isobutenol), benzene + butan-1-ol, +2-methylpropan-1-ol (isobutanol), +2-methyl-2-ene-1-propanol (isobutenol).

Section snippets

Experimental

Excess molar enthalpies were measured at HE and constant pressure, using a C80 calorimeter (Setaram, Lyon, France), a Calvet type microcalorimeter, with no vapor space, the mercury is used to separate the two cells which contained the liquid under study. Details of the equipment and its operation have been described previously [1], [6]. Over most of the mole fraction range, the errors in the mole fractions of the binary mixtures are estimated to be less than 0.001.

Diisopropylether (DIPE) and

Results and discussion

Experimental values of excess molar enthalpies HE at 303.15 K and atmospheric pressure for the six binary mixtures are listed in Table 1, Table 2. These values have been fitted with the following smoothing function, Ref. [9]:HE=xixjk=0ak(xixj)kand standard deviation σ for each representation is defined asσ=(HexpEHcalE)2Nn1/2where N is the number of experimental points and n, the number of parameters of smoothing function (1). Values of coefficients ak and standard deviation σ, are given in

DISQUAC model

The DISQUAC model elaborated by Kehiaian [2], [3] and based on the reticular model of Guggenheim–Barker [15], [16], was applied using the same equations as reported previously [6]. The interactional terms in the thermodynamic properties, GE and HE contain a dispersive (DIS) and a quasi-chemical (QUAC) term, which are calculated, independently by the classical formulas and then simply added.

Conclusion

Using structure-dependant parameters, the model DISQUAC describes consistently the excess functions GE and HE of the investigated systems.

A comparison between experimental data and DISQUAC results is presented in a graphical way in Fig. 1, Fig. 2, Fig. 3, Fig. 4.

    List of symbols

    ak

    parameter of smoothing (Eq. (1))

    xi

    molar fraction of compound, i

    xj

    molar fraction of compound, j

    N

    number of points

    ZE

    excess molar enthalpy HE or Gibbs energy GE in J mol−1

    Exp

    experimental value

    Calc

    calculated value

    σ

    standard deviation in J mol

References (25)

  • H.V. Kehiaian

    Fluid Phase Equilib.

    (1983)
  • K.N. Marsh et al.

    Fluid Phase Equilib.

    (1999)
  • S. Didaoui-Nemouchi et al.

    Fluid Phase Equilib.

    (2007)
  • M. Karvo

    J. Chem. Thermodyn.

    (1980)
  • K. Kammerer et al.

    Thermochim. Acta

    (1998)
  • K. Kammerer et al.

    Fluid Phase Equilib.

    (1999)
  • S. Maken et al.

    J. Chem. Thermodyn.

    (2004)
  • K.C. Singh et al.

    Thermochim. Acta

    (1996)
  • H.V. Kehiaian et al.

    Fluid Phase Equilib.

    (1990)
  • C.R. Chamorro et al.

    Chem. Thermodyn.

    (2002)
  • R.M. Villamaňan et al.

    Fluid Phase Equilib.

    (2006)
  • R.M. Villamaňan et al.

    Fluid Phase Equilib.

    (2006)
  • Cited by (0)

    View full text